1. Field of the Invention
The present invention relates to a display device which displays input image signals on a screen, and a method thereof. More particularly, the present invention relates to a display device which shifts the location of pixels on a screen to prevent a burn-in, and a method thereof.
2. Description of the Related Art
If the same image pattern is displayed on a display device for a long time, a burn-in occurs which leaves an afterimage on a panel. To prevent the burn-in, recently-distributed display devices have a function for shifting a location of the pixels. The function for shifting the location of the pixels, which shifts the location of each pixel at a certain time interval, prevents the burn-in as the fixed image pattern is displayed.
To perform the function for shifting the location of the pixels, a user of the display device may set the shifting distance of the pixels. If the shifting distance of the pixels is set to be large, it can easily prevent the afterimage, but may cause eyestrain due to the intense movement of images on the screen. However, if the shifting distance of the pixels is set to be small, the afterimage may not be effectively prevented, but the image on the screen can be stable as viewed by the user. A user can typically set the shifting distance of the pixels as large as he/she wishes to use the function for shifting the pixels.
The above can be used with panels for a display device which each have a certain resolution. Generally, a panel with 852*480 resolution is considered to be a standard definition (SD) display device, and a panel with 1024*768 resolution is considered to be a high definition (HD) display device.
Various external input signals such as PC signals and DVD reproducing signals besides TV broadcasting signals, may be input to the display device. Accordingly, each input signal also has various input resolutions. Particularly, input signals having various resolutions of 640*480, 800*600, 1024*768, and 1280*768 may be input to the display device.
If the input signal does not have the identical input resolution as the panel resolution, one of the input resolution and the panel resolution is adjusted to display the input signal on the screen. That is, if the input resolution is higher than the panel resolution, the input resolution decreases to be adjusted to the panel resolution. However, if the input resolution is lower than the panel resolution, the panel resolution decreases to be adjusted to the input resolution. At this time, if the panel resolution decreases to be adjusted to the input resolution, the output resolution decreases. Therefore, the size of one pixel becomes larger.
At this time, the moving distance of an image corresponding to the shifting distance of pixels set by the user may be varied. In particular, if the signal of 800*600 resolution is displayed on the display device with a panel of 1024*768 resolution, the panel resolution itself is adjusted to the resolution of 800*600. The size of one dot of 1024*768 resolution is different from the size of one dot of 800*600 resolution. If a user sets the shifting distance of pixels to 2 dots and the pixel moves by 2 dots, the actual moving distance of image becomes larger on the screen. Accordingly, the movement of the image on the screen may become intense enough to cause fatigue in the eyes of the user.
Accordingly, a need exists for a more effective and efficient system and method for shifting the location of pixels on a screen to prevent a burn-in.